A novel crosstalk between Nrf2 and Smad2/3 bridged by two nuanced Keap1 isoforms with their divergent effects on these distinct family transcription factors.

The Keap1-Nrf2 signalling to transcriptionally regulate antioxidant response element (ARE)-driven target genes has been accepted as key redox-sensitive pathway governing a vast variety of cellular stresses during healthy survival and disease development. Herein, we identified two nuanced isoforms α and ß of Keap1 in HepG2 cells, arising from its first and another in-frame translation starting codons, respectively. In identifying those differential expression genes monitored by Keap1α and/or Keap1ß, an unusual interaction of Keap1 with Smad2/3 was discovered by parsing transcriptome sequencing, Keap1-interacting protein profiling and relevant immunoprecipitation data. Further examination validated that Smad2/3 enable physical interaction with Keap1, as well as its isoforms α and ß, by both EDGETSD and DLG motifs in the linker regions between their MH1 and MH2 domains, such that the stability of Smad2/3 and transcriptional activity are enhanced with their prolonged half-lives and relevant signalling responses from the cytoplasmic to nuclear compartments. The activation of Smad2/3 by Keap1, Keap1α or Keap1ß was much likely contributable to a coordinative or another competitive effect of Nrf2, particularly in distinct Keap1-based cellular responses to its cognate growth factor (i.e. TGF-ß1) or redox stress (e.g. stimulated by tBHQ and DTT). Overall, this discovery presents a novel functional bridge crossing the Keap1-Nrf2 redox signalling and the TGF-ß1-Smad2/3 pathways so as to coordinately regulate the healthy growth and development.

The recent advances and future perspectives of genetic compensation studies in the zebrafish model.

Genetic compensation is a remarkable biological concept to explain the genetic robustness in an organism to maintain its fitness and viability if there is a disruption occurred in the genetic variation by mutation. However, the underlying mechanism in genetic compensation remain unsolvable. The initial concept of genetic compensation has been studied in model organisms when there was a discrepancy between knockout-mediated and knockdown-mediated phenotypes. In the zebrafish model, several studies have reported that zebrafish mutants did not exhibit severe phenotype as shown in zebrafish morphants for the same genes. This phenomenon in zebrafish mutants but not morphants is due to the response of genetic compensation. In 2019, two amazing works partially uncovered genetic compensation could be triggered by the upregulation of compensating genes through regulating NMD and/or PTC-bearing mRNA in collaboration with epigenetic machinery in mutant zebrafish. In this review, we would like to update the recent advances and future perspectives of genetic compensation studies, which including the hypothesis of time-dependent involvement and addressing the discrepancy between knockout-mediated and knockdown-mediated to study gene function in the zebrafish model. At last, the study of genetic compensation could be a potential therapeutic strategy to treat human genetic disorder related diseases.

Alleviating experimental allergic eye disease by inhibiting pro-lymphangiogenic VEGFR3 signal.

PURPOSE: Ocular allergy leads to acute and chronic inflammation that may deteriorate the conjunctiva and other ocular tissue. The conjunctiva is covered with abundant lymphatic vessels but how the conjunctival lymphatic system patriciates in the development of allergic eye disease (AED) remains to be elucidated. METHODS AND RESULTS: By using ovalbumin (OVA)+pertussis toxin (PTX) as a sensitizer followed by daily OVA challenges, we induced optimized AED manifestations in mice. We show that conjunctival lymphatics underwent significant expansion after 28 days of chronic OVA challenge, and this process can be prevented by inducible genetic ablation of lymphatic Vegfr3. Through transcriptomic profile analysis in combination with histopathological examinations, we found that pro-lymphangiogenic VEGFR3 signal promoted allergy-induced activation of T helper 2 (Th2) type immune responses, including antigen presentation, and Th2 cells, B cells and mast cell-related pathways in the conjunctiva, thereby critically contributing to the immunoglobulin E (IgE) production and AED manifestations. As a result, ocular allergy can be alleviated by genetic inhibition of lymphatic Vegfr3. Interestingly, pro-lymphangiogenic VEGFR3 signal did not appear to affect the obstruction of meibomian glands (MGs) or the activation of Th17 type and neutrophil pathways that are associated with AED. CONCLUSIONS: These data reveal the key role of pro-lymphangiogenic VEGFR3 signaling in the development of AED and provide experimental evidence that VEGFR3 inhibition may be useful in treating ocular allergy in patients.

Temporal-spatial low shear stress induces heterogenous distribution of hematopoietic stem cell budding in zebrafish.

Hematopoietic stem/progenitor cells (HSPCs) originate from endothelial cells (ECs) localized on the ventral side of the dorsal aorta (DA), and hemodynamic parameters may suffer sharp changes in DA at HSPCs development stage for intersegmental vessel formation. However, the temporal-spatial shear stress parameters and biomechanics mechanisms of HSPC budding remain unknown. Here, we found that the hematopoietic endothelium (HE) in the aorta-gonad-mesonephros was heterogeneous; that is, HEs were mainly distributed at the ventral side of the vascular bifurcation in zebrafish embryos, which was found to show low shear stress (LSS) through numerical simulation analysis. Furthermore, HSPCs localized in the posterior somite of aorta-gonad-mesonephros with slow velocity. On the temporal scale, there was a slow velocity and LSS during HE budding from 36 h post-fertilization and decreased shear stress with drug expanded HSPC numbers. Mechanistically, matrix metalloproteinase (MMP) expression and macrophage chemotaxis were significantly increased in HEs by RNA-seq. After treatment with an MMP13 inhibitor, HSPCs were significantly reduced in both the aorta-gonad-mesonephros and caudal hematopoietic tissue in embryos. Our results show that HSPC budding is heterogeneous, and the mechanism is that physiological LSS controls the emergence of HSPCs by promoting the accumulation of macrophages and subsequent MMP expression.

trans-2-Enoyl-CoA Reductase Tecr-Driven Lipid Metabolism in Endothelial Cells Protects against Transcytosis to Maintain Blood-Brain Barrier Homeostasis.

The transport and metabolism of lipids in cerebrovascular endothelial cells (ECs) have been hypothesized to regulate blood-brain barrier (BBB) maturation and homeostasis. Long-chain polyunsaturated fatty acids (LCPUFAs) as the important lipids components of cell membranes are essential for the development and function of BBB, but the direct links of lipid metabolism and ECs barrier function remain to be established. Here, we comprehensively characterize the transcriptomic phenotype of developmental cerebrovascular ECs in single-cell resolution and firstly find that trans-2-enoyl-CoA reductase (Tecr), a very-long-chain fatty acid synthesis, is highly expressed during barriergenesis and decreased after BBB maturation. EC-specific knockout of Tecr compromises angiogenesis due to delayed vascular sprouting. Importantly, EC-specific deletion of Tecr loss restrictive quality of vascular permeability from neonatal stages to adulthood, with high levels of transcytosis, but maintains the vascular tight junctions. Moreover, lipidomic analysis shows that the expression of Tecr in ECs is associated with the containing of omega-3 fatty acids, which directly suppresses caveolae vesicles formation. These results reveal a protective role for Tecr in BBB integrity and suggest that Tecr as a novel therapeutic target in the central nervous system (CNS) diseases associated with BBB dysfunction.

Noncanonical protease-activated receptor 1 regulates lymphatic differentiation in zebrafish.

The differentiation of lymphatic progenitors is a crucial step in lymphangiogenesis. However, its underlying mechanism remains unclear. Here, we found that noncanonical protease-activated receptor 1 (par1) regulates the differentiation of lymphatic progenitors in zebrafish embryos. Loss of par1 function impaired lymphatic differentiation by downregulating prox1a expression in parachordal lymphangioblasts and caused compromised thoracic duct formation in zebrafish. Meanwhile, the G protein gnai2a, a par1 downstream effector, was selectively required for lymphatic development in zebrafish, and its mutation mimicked the lymphatic phenotype observed in par1 mutants. Interestingly, mmp13, but not thrombin, was required for lymphatic development in zebrafish. Furthermore, analyses of genetic interactions confirmed that mmp13b serves as a par1 upstream protease to regulate lymphatic development in zebrafish embryos. Mechanistically, par1 promotes flt4 expression and phospho-Erk1/2 activity in the posterior cardinal vein. Taken together, our findings highlight a function of par1 in the regulation of lymphatic differentiation in zebrafish embryos.

The blood flow-klf6a-tagln2 axis drives vessel pruning in zebrafish by regulating endothelial cell rearrangement and actin cytoskeleton dynamics.

Recent studies have focused on capillary pruning in various organs and species. However, the way in which large-diameter vessels are pruned remains unclear. Here we show that pruning of the zebrafish caudal vein (CV) from ventral capillaries of the CV plexus in different transgenic embryos is driven by endothelial cell (EC) rearrangement, which involves EC nucleus migration, junction remodeling, and actin cytoskeleton remodeling. Further observation reveals a growing difference in blood flow velocity between the two vessels in CV pruning in zebrafish embryos. With this model, we identify the critical role of Kruppel-like factor 6a (klf6a) in CV pruning. Disruption of klf6a functioning impairs CV pruning in zebrafish. klf6a is required for EC nucleus migration, junction remodeling, and actin cytoskeleton dynamics in zebrafish embryos. Moreover, actin-related protein transgelin 2 (tagln2) is a direct downstream target of klf6a in CV pruning in zebrafish embryos. Together these results demonstrate that the klf6a-tagln2 axis regulates CV pruning by promoting EC rearrangement.

Progress and prospects of mechanotransducers in shear stress-sensitive signaling pathways in association with arteriovenous malformation.

Arteriovenous malformations are congenital vascular lesions characterized by a direct and tangled connection between arteries and veins, which disrupts oxygen circulation and normal blood flow. Arteriovenous malformations often occur in the patient with hereditary hemorrhagic telangiectasia. The attempts to elucidate the causative factors and pathogenic mechanisms of arteriovenous malformations are now still in progress. Some studies reported that shear stress in blood flow is one of the factors involved in arteriovenous malformations manifestation. Through several mechanotransducers harboring the endothelial cells membrane, the signal from shear stress is transduced towards the responsible signaling pathways in endothelial cells to maintain cell homeostasis. Any disruption in this well-established communication will give rise to abnormal endothelial cells differentiation and specification, which will later promote arteriovenous malformations. In this review, we discuss the update of several mechanotransducers that have essential roles in shear stress-induced signaling pathways, such as activin receptor-like kinase 1, Endoglin, Notch, vascular endothelial growth factor receptor 2, Caveolin-1, Connexin37, and Connexin40. Any disruption of these signaling potentially causes arteriovenous malformations. We also present some recent insights into the fundamental analysis, which attempts to determine potential and alternative solutions to battle arteriovenous malformations, especially in a less invasive and risky way, such as gene treatments.

Utility of shape evolution and displacement in the classification of chronic multiple sclerosis lesions.

The accurate recognition of multiple sclerosis (MS) lesions is challenged by the high sensitivity and imperfect specificity of MRI. To examine whether longitudinal changes in volume, surface area, 3-dimensional (3D) displacement (i.e. change in lesion position), and 3D deformation (i.e. change in lesion shape) could inform on the origin of supratentorial brain lesions, we prospectively enrolled 23 patients with MS and 11 patients with small vessel disease (SVD) and performed standardized 3-T 3D brain MRI studies. Bayesian linear mixed effects regression models were constructed to evaluate associations between changes in lesion morphology and disease state. A total of 248 MS and 157 SVD lesions were studied. Individual MS lesions demonstrated significant decreases in volume < 3.75mm3 (p = 0.04), greater shifts in 3D displacement by 23.4% with increasing duration between MRI time points (p = 0.007), and greater transitions to a more non-spherical shape (p < 0.0001). If 62.2% of lesions within a given MRI study had a calculated theoretical radius > 2.49 based on deviation from a perfect 3D sphere, a 92.7% in-sample and 91.2% out-of-sample accuracy was identified for the diagnosis of MS. Longitudinal 3D shape evolution and displacement characteristics may improve lesion classification, adding to MRI techniques aimed at improving lesion specificity.

African Americans experience disproportionate neurodegenerative changes in the medulla and upper cervical spinal cord in early multiple sclerosis.

OBJECTIVE: To compare the temporal changes in the 3-dimensional (3D) structure of the medulla-upper cervical spinal cord region in African American (AA) and white multiple sclerosis (MS) patients to identify early patterns of anatomical change prior to progressive symptom development. METHODS: Standardized 3-Tesla 3D brain MRI studies were performed at two time points on AA and white MS patients along with controls. Longitudinal changes in volume, surface area, tissue compliance, and surface texture measured in total and within ventral and dorsal compartments were studied. Independent regression models were constructed to evaluate differences between groups. RESULTS: Thirty-five individuals were studied, 10 AA with MS (female (F): 8; median age [IQR]=33.8 years (y) [10.9], median disease duration: 11.8y [11.3]), 20 white MS patients (F: 10; 35.6y [17.4], 7.23y [8.83], and 5 controls (F: 2, 51.8y [10.2]). Expanded Disability Status Scale scores were 0.0 at baseline and at the second MRI time point. Within the medulla-upper cervical spinal cord, AA versus white MS patients exhibited greater rates of atrophy in total (p<0.0001) and within the ventral (p<0.0001) and dorsal (p<0.0001) compartments, reduced surface area (p<0.0001), and reduced tissue compliance in the ventral (p=0.002) and dorsal (p=0.0005) compartments. The rate of change at the dorsal surface, but not the ventral surface, between MRI time points was also greater in AA relative to white MS patients (p<0.0001). CONCLUSION: Structural changes in distinct anatomical regions of the medulla-upper cervical spinal cord may be reflective of early and disproportionate neurodegeneration in AA MS as compared to whites.

BOLD signal within and around white matter lesions distinguishes multiple sclerosis and non-specific white matter disease: a three-dimensional approach.

Multiple sclerosis (MS) diagnostic criteria are based upon clinical presentation and presence of white matter hyperintensities on two-dimensional magnetic resonance imaging (MRI) views. Such criteria, however, are prone to false-positive interpretations due to the presence of similar MRI findings in non-specific white matter disease (NSWMD) states such as migraine and microvascular disease. The coexistence of age-related changes has also been recognized in MS patients, and this comorbidity further poses a diagnostic challenge. In this study, we investigated the physiologic profiles within and around MS and NSWMD lesions and their ability to distinguish the two disease states. MS and NSWMD lesions were identified using three-dimensional (3D) T2-FLAIR images and segmented using geodesic active contouring. A dual-echo functional MRI sequence permitted near-simultaneous measurement of blood-oxygen-level-dependent signal (BOLD) and cerebral blood flow (CBF). BOLD and CBF were calculated within lesions and in 3D concentric layers surrounding each lesion. BOLD slope, an indicator of lesion metabolic capacity, was calculated as the change in BOLD from a lesion through its surrounding perimeters. We observed sequential BOLD signal reductions from the lesion towards the perimeters for MS, while no such decreases were observed for NSWMD lesions. BOLD slope was significantly lower in MS compared to NSWM lesions, suggesting decreased metabolic activity in MS lesions. Furthermore, BOLD signal within and around lesions significantly distinguished MS and NSWMD lesions. These results suggest that this technique shows promise for clinical utility in distinguishing NSWMD or MS disease states and identifying NSWMD lesions occurring in MS patients.

Three-Dimensional Lesion Phenotyping and Physiologic Characterization Inform Remyelination Ability in Multiple Sclerosis.

BACKGROUND AND PURPOSE: Multiple sclerosis (MS) clinical management is based upon lesion characterization from 2-dimensional (2D) magnetic resonance imaging (MRI) views. Such views fail to convey the lesion-phenotype (ie, shape and surface texture) complexity, underlying metabolic alterations, and remyelination potential. We utilized a 3-dimensional (3D) lesion phenotyping approach coupled with imaging to study physiologic profiles within and around MS lesions and their impacts on lesion phenotypes. METHODS: Lesions were identified in 3T T2 -FLAIR images and segmented using geodesic active contouring. A calibrated fMRI sequence permitted measurement of cerebral blood flow (CBF), blood-oxygen-level-dependent signal (BOLD), and cerebral metabolic rate of oxygen (CMRO2 ). These metrics were measured within lesions and surrounding tissue in concentric layers exact to the 3D-lesion shape. BOLD slope was calculated as BOLD changes from a lesion to its surrounding perimeters. White matter integrity was measured using diffusion kurtosis imaging. Associations between these metrics and 3D-lesion phenotypes were studied. RESULTS: One hundred nine lesions from 23 MS patients were analyzed. We identified a noninvasive biomarker, BOLD slope, to metabolically characterize lesions. Positive BOLD slope lesions were metabolically active with higher CMRO2 and CBF compared to negative BOLD slope or inactive lesions. Metabolically active lesions with more intact white matter integrity had more symmetrical shapes and more complex surface textures compared to inactive lesions with less intact white matter integrity. CONCLUSION: The association of lesion phenotypes with their metabolic signatures suggests the prospect for translation of such data to clinical management by providing information related to metabolic activity, lesion age, and risk for disease reactivation and self-repair. Our findings also provide a platform for disease surveillance and outcome quantification involving myelin repair therapeutics.

AIBP and APOA-I synergistically inhibit intestinal tumor growth and metastasis by promoting cholesterol efflux.

BACKGROUND: The roles played by cholesterol in cancer development and progression represent a popular field in the cancer community. High cholesterol levels are positively correlated with the risk of various types of cancer. APOA-I binding protein (AIBP) promotes the reverse cholesterol transport pathway (RCT) in cooperation with Apolipoprotein A-I (APOA-I) or high-density lipoprotein cholesterol. However, the combined effect of AIBP and APOA-I on intestinal tumor cells is still unclear. METHODS: Immunohistochemistry, western blot and qPCR were performed to investigate the expression of AIBP and APOA-I in intestinal tumor tissues and cell lines. The anti-tumor activity of AIBP and APOA-I was evaluated by overexpression or recombinant protein treatment. Cholesterol efflux and localization of lipid raft-related proteins were analyzed by a cholesterol efflux assay and lipid raft fraction assay, respectively. RESULTS: Here, we reported that both AIBP expression and APOA-I expression were associated with the degree of malignancy in intestinal tumors. Co-overexpression of AIBP and APOA-I more potently inhibited colon cancer cell-mediated tumor growth and metastasis compared to overexpression of each protein individually. Additionally, the recombinant fusion proteins of AIBP and APOA-I exhibited a significant therapeutic effect on tumor growth in Apcmin/+ mice as an inherited intestinal tumor model. The synergistic effect of the two proteins inhibited colon cancer cell migration, invasion and tumor-induced angiogenesis by promoting cholesterol efflux, reducing the membrane raft content, and eventually disrupting the proper localization of migration- and invasion-related proteins on the membrane raft. Moreover, cyclosporine A, a cholesterol efflux inhibitor, rescued the inhibitory effect induced by the combination of AIBP and APOA-I. CONCLUSIONS: These results indicate that the combination of APOA-I and AIBP has an obvious anticancer effect on colorectal cancer by promoting cholesterol efflux.

FoxF1 is Required for Ciliogenesis and Distribution of Sonic Hedgehog Signaling Components in Cilium.

BACKGROUND: In vertebrates, cilium is crucial for Hedgehog signaling transduction. Forkhead box transcriptional factor FoxF1 is reported to be associated with Sonic Hedgehog (Shh) signaling in many cases. However, the role of FoxF1 in cilium remains unknown. Here, we showed an essential role of FoxF1 in the regulation of ciliogenesis and in the distribution of Shh signaling components in cilium. METHODS: NIH/3T3 cells were serum starved for 24h to induce cilium. Meanwhile, shRNA was used to knockdown the FoxF1 expression in the cells and CRISPR/Cas9 was used to generate the FoxF1 zebrafish mutant. The mRNA and protein expression of indicated genes were detected by the qRT-PCR and western blot, respectively. Immunofluorescence staining was performed to detect the cilium and Shh components distribution. RESULTS: FoxF1 knockdown decreased the cilium length in NIH/3T3 cells. Meanwhile, the disruption of FoxF1 function inhibited the expression of cilium-related genes and caused an abnormal distribution of Shh components in the cilium. Furthermore, homozygous FoxF1 mutants exhibited defective development of pronephric cilium in early zebrafish embryos. CONCLUSION: Together, our data illustrated that FoxF1 is required for ciliogenesis in vitro and in vivo and for the proper localization of Shh signaling components in cilium.

Effect of simulated microgravity induced PI3K-nos2b signalling on zebrafish cardiovascular plexus network formation.

Local abnormal angiogenesis and cardiovascular system reorganization have been observed in embryos exposed to a simulated microgravity (SM) environment. In this study, changes in key molecular signals and pathways in cardiovascular development have been investigated under microgravity conditions. In particular, the caudal vein plexus (CVP) network, formed by sprouting angiogenesis has been chosen. Zebrafish embryos were exposed to SM using a ground-based microgravity bioreactor for 24 and 36 h. The SM was observed to have no effect on the zebrafish length, tail width and incubation time whereas it was observed to significantly reduce the heart rate frequency and to promote abnormal development of the CVP network in the embryos. Nitric oxide (NO) content demonstrated that the total proteins in zebrafish embryos were significantly higher in SM than in the control group grown under normal conditions. It was then preliminarily determined how NO signals were involved in SM regulated zebrafish CVP network formation. nos2b MO was injected and CVP network evolution was observed in 36 h post fertilization (hpf) under SM condition. The results showed that the CVP network formation was considerably decreased in the nos2b MO treated group. However, this inhibition of the CVP network development was not observed in control MO group, indicating that nos2b is involved in the SM-regulated vascular development process in zebrafish. Moreover, specific phosphoinositide 3-kinase (PI3K) inhibitors such as LY294002 were also tested on zebrafish embryos under SM condition. This treatment significantly inhibited the formation of zebrafish CVP network. Furthermore, overexpression of nos2b partly rescued the LY294002-caused CVP network failure. Therefore, it can be concluded that SM affects zebrafish CVP network remodeling by enhancing angiogenesis. Additionally, the PI3K-nos2b signaling pathway is involved in this process.

Beneficial effects of Enterococcus faecalis in hypercholesterolemic mice on cholesterol transportation and gut microbiota.

Hypercholesterolemia plays a critical role in the development of atherosclerosis and cardiovascular diseases. Many works have been reported that gut microbiota could affect hypercholesterolemia through cholesterol metabolism. However, the role of gut microbiota on cholesterol transportation remains unclear. In this study, 8-week-old C57BL/6J mice were fed with high-cholesterol diet to build the hypercholesterolemic mice. Then, the hypercholesterolemic mice got the oral administration of Enterococcus faecalis ATCC19433 at a dose of 109 CFU/mL/day or PBS with high-cholesterol diet for 4 weeks. Serum was collected to detect the concentration of total cholesterol (TC). Meanwhile, pathology, histology, real-time polymerase chain reaction, Western blot, and immunofluorescence were used to evaluate the expression of ABCG5 and ABCG8 in the liver and small intestine. We also analyzed the composition of gut microbiota through high-throughput sequencing method. Oral administration of E. faecalis ATCC19433 significantly decreased the concentration of serum cholesterol in hypercholesterolemic mice. Furthermore, E. faecalis ATCC19433 reduced the concentration of liver cholesterol and improved cholesterol by increasing the expression of ABCG5 and ABCG8. Moreover, oral administration of E. faecalis ATCC19433 modulated the composition of gut microbiota and increased the counts of Lactobacillus, Bifidobacterium, and Akkermansia. Our results showed that E. faecalis ATCC19433 could exert hypocholesterolemic effect on hypercholesterolemic mice by improving transporter ABCG5 and ABCG8. E. faecalis ATCC19433 maybe contribute to the transportation of cholesterol potentially and modulate the composition of gut microbiota.

Overview of Crosstalk Between Multiple Factor of Transcytosis in Blood Brain Barrier.

Blood brain barrier (BBB) conserves unique regulatory system to maintain barrier tightness while allowing adequate transport between neurovascular units. This mechanism possess a challenge for drug delivery, while abnormality may result in pathogenesis. Communication between vascular and neural system is mediated through paracellular and transcellular (transcytosis) pathway. Transcytosis itself showed dependency with various components, focusing on caveolae-mediated. Among several factors, intense communication between endothelial cells, pericytes, and astrocytes is the key for a normal development. Regulatory signaling pathway such as VEGF, Notch, S1P, PDGFß, Ang/Tie, and TGF-ß showed interaction with the transcytosis steps. Recent discoveries showed exploration of various factors which has been proven to interact with one of the process of transcytosis, either endocytosis, endosomal rearrangement, or exocytosis. As well as providing a hypothetical regulatory pathway between each factors, specifically miRNA, mechanical stress, various cytokines, physicochemical, basement membrane and junctions remodeling, and crosstalk between developmental regulatory pathways. Finally, various hypotheses and probable crosstalk between each factors will be expressed, to point out relevant research application (Drug therapy design and BBB-on-a-chip) and unexplored terrain.

Microcystin-LR induces angiodysplasia and vascular dysfunction through promoting cell apoptosis by the mitochondrial signaling pathway.

The harmful algal blooms are becoming increasingly problematic in the regions that drinking water production depends on surface waters. With a global occurrence, microcystins are toxic peptides produced by multiple cyanobacterial genera in the harmful algal blooms. In this study, we examined the effects of microcystin-LR (MC-LR), a representative toxin of the microcystin family, on vascular development in zebrafish and the apoptosis of human umbilical vein endothelial cells (HUVECs). In zebrafish larvae, MC-LR induced angiodysplasia, damaged vascular structures and reduced lumen size at 0.1 µM and 1 µM, leading to the decrease of the blood flow area in the blood vessels and brain hemorrhage, which showed that MC-LR could dose-dependently inhibit vascular development and cause vascular dysfunction. In MC-LR treated HUVECs, the proportion of early apoptosis and late apoptosis cells increased in a concentration-dependent manner. Different concentrations of MC-LR could also activate caspase 3/9 in HUVECs, increase the level of mitochondrial ROS and reduce mitochondrial membrane potential. Additionally, MC-LR could promote the expression of p53 and inhibit the expression of PCNA. The findings showed that MC-LR could promote apoptosis of HUVECs through the mitochondrial signaling pathway. Combined with these results, MC-LR may promote vascular endothelial cell apoptosis through mitochondrial signaling pathway, leading to angiodysplasia and vascular dysfunction.

Post-gadolinium 3-dimensional spatial, surface, and structural characteristics of glioblastomas differentiate pseudoprogression from true tumor progression.

PURPOSE: Pseudoprogression is often indistinguishable from true tumor progression on conventional 2-dimensional (2D) MRI in glioblastoma multiforme (GBM) patients. The aim of this study was to determine the association between post-gadolinium 3-dimensional (3D) characteristics and clinical state in GBM patients. METHODS: Standardized 3D brain MRI studies were performed, and contrast enhancing portions of each tumor were segmented and analyzed, blinded to clinical state, using principal component analysis (PCA), medial axis transformation (MAT), and coverage analysis. Associations between the 3D characteristics of the post-gadolinium enhanced regions and the clinical status of patients were performed. RESULTS: A total of 15 GBM patients [male: 11 (73%); median age (range): 62 years (36-72)] with a median disease duration of 6 months (range 2-24 months) were studied cross-sectionally with 6 (40%) patients identified with tumor progression. Post-gadolinium features corresponding to the group with progressive disease exhibited a more spherical and symmetric shape relative to their stable counterparts (p = 0.005). The predictive value of a more uniformly full post-gadolinium enhanced shell to clinical progression was determined with a sensitivity of 66.7% (95% CI 29.9-92.5), specificity of 100% (54.1-100), and PPV of 100% (p = 0.028, 2-tailed Fisher's exact test). There did not appear to be an association between the thickness of the contrast enhanced shell to clinical state. CONCLUSIONS: The application of 3D technology with post-gadolinium imaging data may inform healthcare providers with new insights into disease states based on spatial, surface, and structural patterns.

GPR126 protein regulates developmental and pathological angiogenesis through modulation of VEGFR2 receptor signaling.

Angiogenesis, the formation of new blood vessels from pre-existing ones, is essential for development, wound healing, and tumor progression. The VEGF pathway plays irreplaceable roles during angiogenesis, but how other signals cross-talk with and modulate VEGF cascades is not clearly elucidated. Here, we identified that Gpr126, an endothelial cell-enriched gene, plays an important role in angiogenesis by regulating endothelial cell proliferation, migration, and tube formation. Knockdown of Gpr126 in the mouse retina resulted in the inhibition of hypoxia-induced angiogenesis. Interference of Gpr126 expression in zebrafish embryos led to defects in intersegmental vessel formation. Finally, we identified that GPR126 regulated the expression of VEGFR2 by targeting STAT5 and GATA2 through the cAMP-PKA-cAMP-response element-binding protein signaling pathway during angiogenesis. Our findings illustrate that GPR126 modulates both physiological and pathological angiogenesis through VEGF signaling, providing a potential target for the treatment of angiogenesis-related diseases.